A SPD (Surge Protection Device) is directed to protecting the damages of a certain system from a surge voltage which generally occurs due to lightening, etc. Most of the current electric devices, electronic circuits, communication devices, etc. are configured to include an integrated circuit having low power and high integrations, so they might be easily damaged by a relatively low surge voltage.
It is a trend that many products are equipped with a surge protection device for the purpose of effectively protecting the internal circuits from a surge voltage. The above mentioned surge protection device generally comprises a diverting type device like a lightening rod configured to limit an overvoltage with a breakdown device by diverting a propagation route of an over current occurring on a line to the ground, a blocking type device generally formed of a resistor or an inductor configured to prevent an overvoltage from transferring to a system which will be protected, by limiting the passage of an over current, and a clamping type device of a MOV (Metal Oxide Varistor) or a constant voltage diode, etc. which are generally configured to limit a certain level of incoming overvoltage to a limited voltage of the device.
In case of the above described surge protection device, the lifespan of a surge protection device is determined depending on the number of lightening or surge inputs or the level of lightening surges. For this reason, a surge protection device installed one month ago might be replaced with a new one
In the event that the surge protection device is not replaced for the sake of a continuous use, the surge absorption device (for example, MOV, Varistor, etc.) installed in the surge protection device might be degraded, so a short circuit, not a disconnection, occurs as the lifespan ends, which consequently results in a formation of a closed circuit for thereby causing ignition or explosion. The problem encountered in the conventional art is that it is impossible to know or estimate the lifespan of a surge protection device. The lifespan of the surge protection device can be known only when damages actually occur and are visually checked.
According to the conventional surge protection device, it is impossible to check the amount of the leakage currents flowing to the ground, due to which the electric power might be unnecessarily consumed for the leakage currents.
In addition, it is impossible to check whether the surge protection device is properly installed on the ground line, so the normal operations of the installed surge protection device cannot be checked.
According to the conventional surge protection device, it is impossible to obtain the date and time-based statistic data on the leakage current of the surge protection device, the number of surge occurrences, the levels of the surges, and the ground states.